Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon. Many integrated circuits are typically manufactured on a single semiconductor wafer, and individual dies on the wafer are singulated by sawing between the integrated circuits along a scribe line. The individual dies are typically packaged separately, in multi-chip modules, or in other types of packaging, for example.
An image sensor is used to convert an optical image focused on the image sensor into an electrical signal. The image sensor includes an array of light-detecting elements, such as photodiodes, and a light-detecting element is configured to produce an electrical signal corresponding to the intensity of light impinging on the light-detecting element. The electrical signal is used to display a corresponding image on a monitor or provide information about the optical image.
Although existing image sensor device structures and methods for forming the same have been generally adequate for their intended purpose, they have not been entirely satisfactory in all aspects.